Recent estimates of U.S. HIV incidence indicate that young people aged 13 to 25 account for more than a 25% of new infections, with the majority of cases among young men who have sex with men (YMSM). While official incidence statistics are not differentiated by transgender status, local estimates indicate extremely high rates of unrecognized HIV infection among young transgender women (YTW). Substance use, particularly alcohol misuse, has been identified as a driver of sexual risk and a potential barrier to engagement in the HIV prevention and care continuum (i.e., Seek, Test, Treat, Retain) among YMSM and YTW, but these youth are difficult to reach for substance use services due in part to marginalized status and poor access to health care. YMSM and YTW, however, often seek HIV testing and other supportive services in community-based and outreach settings. These settings are underutilized as potential entry points for engagement in comprehensive care across the HIV prevention and care continuum, which now extends to the use of pre-exposure prophylaxis (PrEP) for high risk HIV-negative youth. To capitalize on this opportunity, we propose to test a structural change to the Seek, Test, Treat and Retain (STTR) model by integrating substance use screening and brief intervention into the traditional community-based HIV testing environment. We will couple STTR with Screening & Brief Intervention (SBI) for substance use at the point of HIV testing, adapting SBI for electronic deployment (eSBI) in community-based environments that target YMSM and YTW. The purpose of this study is to test the feasibility, acceptability and initial efficacy of eSBI coupled with STTR (intervention) in comparison to STTR only (control) among YMSM and YTW in community-based HIV testing environments in Chicago and to assess and describe intervention effects on engagement within the HIV and PrEP care continuum. We will do this with the following aims: Aim 1: Assess the feasibility, acceptability and initial efficacy of electronic Screening & Brief Intervention (eSBI)+ Seek, Test, Treat and Retain (STTR) compared to STTR-only to reduce alcohol and other substance use among 450 YMSM and YTW in Chicago, ages 16-25; Aim 2: To explore the initial efficacy of eSBI+STTR in comparison to STTR-only on secondary exploratory outcomes within the HIV and PrEP care continuum among YMSM and YTW. The proposed study is highly responsive to RFA-DA-15-019 by seeking to test empirically-based interventions for substance use within the HIV care continuum among understudied and high-risk populations. Together, the research team has substantial experience with SBI as well as the target populations, YMSM and YTW, to effectively engage them in the proposed research. Study findings have the potential to change the structure of the HIV testing paradigm for these youth at high risk of HIV infection by imbedding substance use screening and intervention into the traditional HIV testing environment, within a portable and reproducible framework that is generalizable to community-based contexts.